DESCRIPTION (Verbatim from the Applicant's Abstract): Experimental work done to date indicates that Opto-Acoustic Tomography will provide breast images with greater contrast and sensitivity to cancer than the currently preferred methods. In a Laser Optoacoustic Imaging System (LOIS) short near-infrared laser pulses are absorbed preferentially in tumors to generate pressure profiles resembling distribution of absorbed optical energy in the breast. Variation of the laser wavelength permits targeting either blood-rich malignant carcinoma or fibrous-tissue-rich fibroadenoma. Therefore, pressure waves emanating from tumors deliver information to the breast surface not only about the location and dimensions of tumors, but also diagnostic information. At the breast surface signals are detected by wide-band, piezoelectric transducers and analyzed to generate an image. Extensive laboratory research has proven the practicality and significant advantages of LOIS. LOIS is suitable for examination of all breasts independently on skin color, age and radiological density. The goal of the work proposed is to develop a commercial prototype instrument. The work during the Phase I project will focus on the general design, design of system components and fabrication of an advanced opto-acoustic array detector. Fabricated system components will be employed in the clinical research system at UTMB and tested with five breast cancer patients. PROPOSED COMMERCIAL APPLICATION: The proposed work will ultimately lead to a commercial device that will be useful as a primary tool in screening for breast cancer and as a secondary imaging tool for reduction of the large number of false positives generated by other screening procedures, such as X-ray mammography. The estimated cost per examination will be comparable to that for an ultrasonic image. The device will be suitable for guiding needle biopsies of suspicious lesions and new thermal therapeutic methods (such as focused ultrasound or laser, fiber-optic ablation) for eradication of those lesions. A potential for eventual application of the equipment in various diagnostic, monitoring and therapeutic procedures will guide further design considerations.